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Leucopaxillus gentianeus

[ Basidiomycetes > Agaricales > Tricholomataceae > Leucopaxillus . . . ]

by Michael Kuo

When fresh and young, this western Leucopaxillus is easily separated from other species in the genus on the basis of its cap color, which is dark liver brown--but older, faded specimens of Leucopaxillus gentianeus can be more or less indistinguishable from other mushrooms in the Leucopaxillus albissimus complex, and beginners might confuse even the young specimens with a variety of superficially similar mushrooms (including species of Tricholoma and Russula; see the list of features on the page for the genus Leucopaxillus for help eliminating these contenders).

Singer & Smith (1943) document 10 forms and "subforms" (?!) of Leucopaxillus amarus (the former name for Leucopaxillus gentianeus), primarily on the basis of taste, degree of pigmentation, and size. You are welcome to go down that road if you'd like (ask your library to procure Papers of the Michigan Academy of Science 28: 85-132), but I have a feeling you have better things to do.


Ecology: Saprobic, decomposing the litter of conifers (also reported under oaks and Eucalyptus on the West Coast); growing scattered, gregariously, or in arcs or fairy rings; widely distributed in western North America from the Rocky Mountains westward; summer, fall, and winter.

Cap: 5-15 cm; convex with an inrolled margin when young, becoming broadly convex, flat, or shallowly depressed; dry; fairly smooth; liver brown or reddish brown when young, but often fading with age; the margin usually broadly lined at maturity.

Gills: Attached to the stem or running down it; close; separable from the cap as a layer; whitish to dirty yellowish when mature; sometimes developing rusty spots.

Stem: 4-10 cm long; up to 3 cm thick; when young often slightly swollen near the base but by maturity usually more or less equal; fairly smooth; whitish, sometimes discoloring brownish on handling; with prominent and copious basal mycelium.

Flesh: White; thick; hard; not changing on exposure.

Odor and Taste: Odor not distinctive or (more commonly) mealy to foul (like coal tar or swamp gas); taste bitter.

Spore Print: White.

Chemical Reactions: KOH on cap surface negative.

Microscopic Features: Spores 4-6 x 3-5 µ (including ornamentation); nearly round; spiny with amyloid warts. Cheilocystidia abundant; variously shaped; to about 40 µ. Pleurocystidia absent. Elements of pileipellis often with pigment-incrusted walls.

Leucopaxillus amarus is a synonym.

REFERENCES: (Quélet, 1873) Kotlaba, 1966. (Saccardo, 1887; Singer & Smith, 1943; Arora, 1986; States, 1990; Phillips, 1991/2005; Lincoff, 1992; Evenson, 1997; Miller & Miller, 2006.) Herb. Kuo 01140502.

Further Online Information:

Leucopaxillus gentianeus at MykoWeb
Leucopaxillus gentianeus at Roger's Mushrooms
Leucopaxillus gentianeus at Agaricales of the Hawaiian Islands


Leucopaxillus gentianeus

Leucopaxillus gentianeus

Leucopaxillus gentianeus

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Cite this page as:

Kuo, M. (2007, February). Leucopaxillus gentianeus. Retrieved from the MushroomExpert.Com Web site: